Locking-keys for turbine-generator retaining rings



R. A. BAU DRY May 27, 1958 LOCKING-KEYS FOR TURBINE-GENERATOR RETAINING RINGS Filed May 5. 1954 United States Patent LOCKING-KEYS FOR TURBINE-GENERATOR RETAINING RINGS Ren Andr Baudry, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pin, a corporation of Pennsylvania Application May 5, 1954, Serial No. 427,823

8 Claims. (Cl. 28752) My invention relates to an open ring-shaped lockingkey which is inserted between the retaining ring and the rotor-core of a turbine-generator, or between the retaining ring and its end-plate, or, in general, between any two telescopically fitting parts of a two-part cylindrical member of any kind. In the field of turbine-generator retaining-rings, my invention is an improvement over the construction which is shown in the Vickers Patent 2,621,223, December 9, 1952, which is an improvement over the practices shown in the Hill Patent 2,318,074, May 4, 1943; the Rose Patent 1,890,340, December 6, 1932; and the Kilgore Patent 2,094,358, September 28, 193.7.

The general object of my invention is to provide a new, strong, simple and inexpensive locking-ring, which provides a larger contact-area than is obtainable with the discrete locking-plungers of the Vickers patent, and which avoids the necessity for drilling and tapping a number of small-radial holes in the retaining ring in order to radially compress the locking-ring by means of jack-screws, as in other locking means of the prior art. These previously used small tapped holes created stress-concentrations whichwere undesirable in the larger sizes of retaining rings, and these holes were also quite difiicult to drill and tap in the non-magnetic steel material of which most of the larger retaining rings are made.

My present invention provides a locking-device by means of which it is possible to contract the lockingring or key by providing the locking-ring with lateral notches or other conformations suitable for accommodating a Wedge, lever, or other axially extending tool, for. applying a radial force on said locking-key at each of a plurality of points, thereby avoiding the previously mentioned difficulties, and yet providing a means for directly compressing the locking-ring at any point at which it may have become stuck by varnish or rust.v This invention can be used either with or without an additional means for contracting the locking-ring by pulling together the ends of the ring, as described and claimed in an application of Michael Rashevsky, Serial No. 427,731, filed May 5, 1954 now Patent No. 2,792,513.

Several exemplary forms of embodiment of my invention are shown in the accompanying drawing, where- Figure l is a longitudinal sectional view of a portion of the rotor-member of a turbine generator, showing one of my radial-pressure means for depressing the lockingring between the retaining ring and the end-plate, and showing one of theRashevsky circumferentially acting means for contracting the locking-ring between the retaining ring and the rotor body, the section-plane being indicated at I-I in Fig. 3;

Fig. 2 is a fragmentary longitudinal sectional view showing an alternative'form of radially active depressingmeans, which could be used at either end of the retaining ring, the section plane being indicated at IL-ll in Fig. 3;

Fig.3 is a fragmentary transverse sectional view through the rotor body, looking toward the retaining ring,

- engaged by a locking-key means,

2,836,445 Patented May 27, 1958 as indicated by the section plane line III-III in Fig. 1; and

Figs. 4 and 5 are fragmentary longitudinal sectional views showing elevations of alternative types of levers which can be used as the radially acting depressing-tools for the respective ends of the retaining ring.

In the drawing, I show a part of only the rotor-member 6 of a turbine-generator or other high-speed dynamoelectric machine. The illustrated part of the rotormember comprises a slotted cylindrical rotor-core or body 7, a rotor-winding 8, and one of the two retaining rings 9 which extend beyond the respective ends of the rotorcore.

The slotted cylindrical rotor-core 7 is provided with slotted winding-carrying portions 11, alternating with poleface portions 12. The winding-carrying portions 11 have winding-receiving slots 13 which extend throughout the entire length of the rotor body for receiving the coilsides 14 of the rotor-winding, these coilsides being retained by slot-closing wedges 15. The pole-portions 12 usually do not have axially extending slots which extend throughout the entire core-length, but these portions may be provided with inclined access-slots 16a, 16b and 16c, which are cut radially and longitudinally or axially into the periphery of the rotor body at each end of at least one of said pole-face portions 12.

The rotor-winding 8 is a direct-current field-winding, usually providing two poles in the commonest fields of application of my invention. This rotor-winding 8 has the previously mentioned coil-side portions 14, which lie in the winding-receiving slots 13, and also end-turn portions 17, which lie beyond the respective ends of the rotor-core 7, and which are retained against centrifugal force, by means of the retaining rings 9.

The inner end of each retaining ring 9 has a cylindrical bore which fits telescopically over its end of the rotorcore 7. The telescoped portions, which are the engaging surfaces of the telescoping parts 9 and 7, have opposite annular grooves or slots'9' and 7 which are complementary to form a substantially closed annular chamber. The outer end of each retaining ring 9 fits telescopically over an end-plate 18. The telescoped portions, which are the engaging surfaces of the telescoping parts 9 and 13, have opposite annular grooves or slots 9" and 18 which are complementary to form a substantially closed annular chamber. Preferably, the retaining-rings 9 are shrunk onto the rotor-core or body 7, and they may also be shrunk onto their respective end-plates 18.

Each of the pairs of opposite annular grooves, 7'-9' and 9"--18, of the telescoped portions are lockingly which is preferably, but not necessarily, a single-piece, open-ended, ring-shaped locking-key 19 or 19", whichfits within and between these opposite grooves to retain the retaining ring on the rotor-core '7 and the end-plate 18, respectively. These locking-keys 19' and 19" are preferably resiliently biased toward an expanded position. Each of these lockingkeys has one or more pairs of, nearly abutting ends 21 and 22, which are separated far enough to admit of the contraction of the locking-key or'ring sufficiently to clear the groove 9' or 9 in the retaining ring 9 which constitutes the outer member of the two telescoped parts in each case. a 7

According to my present invention, each of the lock ing-rings or keys l9 and 19" is provided, at each of a plurality of points spaced therealong, with a lateral groove 23 (Figs. 1, 4 and 5), or a wedge-shaped cross-notch 24 (Figs. 2 and 3), or other conformation suitable for accommodating an axially extending tool which makes it possible to apply a radial force for depressing thelocking-key or ring 19 or 19 at any one or more of said plurality of spaced points, thus reducing the diameter '7 s) of the locldng-key, so as to permit disassembly of the parts. This radial-depression tool may take any one or"v a number of forms.

Thus, in Fig. l, l show a rocking-tool 25 for the removal of the-end-plate 18. it comprises a bodymemher 25s, to the lower portion of which is secured a steel bar 25b. This bar 25b extendsthrough a lateral hole 26 in the end-plate 13, and it terminates in a reduced end 250 for engaging one of the lateral grooves 23 of the locking-ring 19''. The lower portion of the body-member 25a is also provided with one or more fulcrum-lugs 25d which are adapted to engage the end of the end-plate 18 at about the same level or radial height as the locking-key 19". The top portion of the body-member 25a is provided with a jacking-bolt 25a, which is adapted to be tightened down into a tapped hole 25f which is drilled and tapped into the end-plate it Thus, when the jacking-bolt 25a is tightened, the reduced end 25c of the bar 25!) is moved downwardly, so that it radially depresses the locking-key or ring 19', so as to enable it to clear the annular groove 9" in the retaining ring 9.

Another form of the radial-depression axially extending tool is shown in Figs. 2 and 3, in the form of an axially movable wedge 27 (Fig. 2), which can be placed over one or more of the slot-closing wedges 15 of the rotor-member, with its pointed or wedge-shaped end overlying the wedge-shaped cross-notch 24 in the lockingkey 19, so that, when this wedge is pushed or driven underneath the overhanging inner end 912 of the retaining ring 9, it will radially depress the locking-key 19.

This may be done at as many points as may be necessary, around the circumference of the locking-ring 19, so as to depress this ring sufiiciently to clear the annular groove 9 in the retaining ring 9, so that the retaining n ring can be removed from the rotor body 7.

In Fig. 4, the radial-depression rocking-tool 25 of Fig. l is replaced by a simple rocking-lever 28, which has a reduced end 280 for engaging the lateral groove 23 in the locking-key l9", and which is also provided with an upwardly extending fulcrum-lug 28d which engages the top or" the hole 26 in the end-plate 18, through which the lever 28 extends.

In Fig. 5, the wedge-shaped radially depressing tool 27 of Fig. 2 is replaced by a rocking-lever 29, which has a reduced end 29c for engaging the lateral groove 23 in the locking-key 19', and which is also provided with an upwardly extending fulcrum-lug 29:1 for pressing up against the overhanging inner end 9:: of the retaining ring 9, whereby a downward pressure can be exerted on the locking-key 19' at as many points as may be necessary to clear it out of the annular groove 9', so as to make possible the removal of the retaining ring 9 from the rotor body 7.

In each of the forms of embodiment of my invention, and as more specifically shown in Fig. 3, the locking-key or ring 19' or 19" may be provided, at any suitable point or points, with pins 31 and 32 for locating the locking-key and preventing its circumferential movement within the annular grooves 9'7 or 9"18", as the case may be.

It will sometimes be desirable to apply my radialdepression means, in any one of its forms, for radially depressing the locking-keys or rings 19' or 19", to a form of locking-key or ring which is also provided with a means for applying a circumferential force for pulling or drawing the nearly abutting ends 21 and 22 of the locking-key, such as 19. Such a circumferentially pulling means is shown at the core end of the retaining ring 9 in Fig. l, and it also constitutes the subject matter of the e previously mentioned Rashevsky application. To use such a circumferentially pulling means, the locking-key or ring 19 is provided, near each of its nearly abutting ends 21 andv 22, with a lateral notch or hole 33, which may be engaged by pins 34 in any suitable tool for applying a strong tangential or circumferential force for pulling the nearly abutting ends 31 and 32 together, so as to reduce the diameter of the locking-key 19', thus clearing it out of the annular groove 9' in the retaining ring 9, so as to permit a disassembling of the parts. The groove 7' of the inner telescoping part 7 has sufficient death to permit the locking-key 19' to be moved completely out of the groove 9 of the outer telescoping part 9, so as to permit this disassembly.

To be feasible, this circumferential-pressure tool or means should be a detachable or disengageable tool which extends heyond the inner end of the retaining ring 9, which is the outer one of the two telescoping parts 9 and 7. A convenient tool for this purpose is that which is shown in my Fig. 1, and which is described and claimed in the Rashevsky application. It is a tension-applying tool 35, having two intermediately pivoted legs which are pivotally joined at an intermediate point 35c. This double-legged tension-applying tool 35 is adapted to stand radially in the access-slots 16a and 16b, when the retaining ring 9 is to be removed from the rotor body 7. The bottom ends of the two legs 35a and 35b are provided with strong oifset bottom-portions which extend axially or longitudinally under the inner telescoping end 9a of the retaining ring 9, and which terminate in the pins 34 which come into removable engagement with holes 33 near the ends 21 and 22 of the locking-key 19'. These two key-ends 21 and 22 may then be drawn together by forcing the upper ends of the tool-legs apart, as by means of a screw 35 In some cases, it may be preferable to provide a tension-applying tool, such as 35, and to use it as the normal means for disengaging the locking-key or ring, suchas l9, whenever it becomes necessary to remove the retaining ring 9 from the rotor-body 7. It happens occasionally, but often enough so that provision must be made for it, that the locking-key 19 may have become tightly stuck, either because of varnish or rust, so that it'is not possible to apply enough tangential or circumferential tension to draw all portions of the locking-key inwardly, far enough to disengage all portions of the annular groove 9. To provide for such contingencies, it is necessary to make provision for some radially depressing,

axially extending tool, such as the tools 25, 27, 28 or 29, or any equivalent means, whereby the locking-key 19' may be dislodged, or forcibly driven inwardly, at sufficiently closely spaced points all the way around its circumference.

While I have described my invention in only a few illustrative forms of embodiment, I wish it to be understood that equivalent devices may be substituted, and other necessary cooperative parts may be added, or some parts may be omitted, as occasion may demand, without departing from the essential spirit of my invention.

1 claim as my invention:

1. The combination including a cylindrical body-part, a ring-part which extends beyond one end of said cylindrical body-part, the inner end of said ring-part having a cylindrical bore which fits telescopically over said end of the cylindrical body-part, the engaging surfaces of the two telescoping parts having opposite annular grooves which are complementary to form a substantially closed annular chamber, and a locking-key means fitting within and between said opposite grooves to retain said parts together, said locking-key means having one or more pairs of nearly abutting ends, said locking-key means being provided, at each of a plurality of points spaced therealong, with a conformation suitable for accommodating an axially extending tool for applying a radial force on said locking-key means, so as to depress the locking-key radially and thus reduce its diameter to permit disassembly of the parts, the groove of the inner telescoping part having suflicient depth to permit the locking-key to be moved completely out of the grooveof the outer telescoping part so as to permit said disassembly, and the inner one of said cylindrical parts being provided, at each of said plurality of points, with an axially extending opening for accommodating such a tool.

2. The combination including a cylindrical body'part, a ring-part which extends beyond one end of said cylindrical body-part, the inner end of said ring-part having a cylindrical bore which fits telescopically over said end of the cylindrical body-part, the engaging surfaces of the two telescoping parts having opposite annular grooves which are complementary to form a substantially closed annular chamber, and a locking-key means fitting within and between said opposite grooves to retain said parts together, said locking-key means having one or more pairs of nearly abutting ends, said locking-key means being provided, at each of a plurality of points spaced therealong, with a conformation suitable for accommodating an axially extending tool for applying a radial force on said locking-key means, so as to depress the locking-key radially and thus reduce its diameter to permit disassembly of the parts, the one or more pairs of nearly abutting ends of said locking-key means being provided with means for accommodating a tool extending beyond the end of the outer telescoped part for applying a circumferential force on said locking-key means, so as to pull said nearly abutting ends toward each other and thus also reduce the diameter of the locking-key to permit disassembly of the parts, the groove of the inner telescoping part having sufficient depth to permit the locking-key to be moved completely out of the groove of the outer telescopingpart so as to permit said disassembly, and the inner one ofsaid cylindrical parts being provided, at each of said plurality of points, and also in the vicinity of said nearly abutting ends, with an axially extending opening for accommodating such tools.

3. The combination including a cylindrical body-part, a ring-part which extends beyond one end of said cylindrical body-part, the inner end of said ring-part having a cylindrical bore which fits telescopically over said end of the cylindrical body-part, the engaging surfaces of the two telescoping parts having opposite annular grooves which are complementary to form a substantially closed annular chamber, and a locking-key means fitting within and between said opposite grooves to retain said parts together, said locking-key means having one or more pairs of nearly abutting ends, said locking-key means being provided, at each of a plurality of points spaced therealong, with means for applying a radial force on said locking-key means, so as to depress the locking-key radially and thus reduce its diameter to permit disassembly of the parts, the one or more pairs of nearly abutting ends of said locking-key means being provided with means for applying a circumferential force on said locking-key.

means, so as to pull said nearly abutting ends toward each other and thus also reduce the diameter of the locking-key to permit disassembly of the parts, the groove of the inner telescoping part having suflicient depth to permit the locking-key to be moved completely out of the groove of the outer telescoping part so as to permit said disassembly, and the inner one of said cylindrical parts being provided, at each of said plurality of points, and also in the vicinity of said nearly abutting ends, with an axially extending opening for accommodating such forceapplying means.

4. The combination including a cylindrical body-part, a ring-part which extends beyond one end of said cylindrical body-part, the inner end of said ring-part having a cylindrical bore which fits telescopically over said end of the cylindrical body-part, the engaging surfaces of the two telescoping parts having opposite annular grooves which are complementary to form a substantially closed annular chamber, and an open ring-shaped locking-key fitting within and between said opposite grooves to retain said parts together, said locking-key being resiliently biased toward an expanded position, said locking-key being provided, at each of a plurality of points spaced therealong, with a conformation suitable for accommodating an axially extending tool for applying a radial force on said locking-key, so as to depress the lockingkey radially and thus reduce its diameter to permit disassembly of the parts, the groove of the inner telescoping part having suificient depth to permit the locking-key to be moved completely out of the groove of the outer telescoping part so as to permit said disassembly, and the inner one of said cylindrical parts being provided, at each of said plurality of points, with an axially extending opening for accommodating such a tool.

5. The combination including a cylindrical body-part, a ring-part which extends beyond one end of said cylindrical body-part, the inner end of said ring-part having a cylindrical bore which fits telescopically over saidend of the cylindrical body-part, the engaging surfaces of the two telescoping parts having opposite annular grooves which are complementary to form a substantially closed annular chamber, and an open ring-shaped locking-key fitting within and between said opposite grooves to retain said parts together, said locking-key being resiliently biased toward an expanded position, said locking-key being provided, at each of a plurality of points spaced therealong, with a conformation suitable for accommodating an axially extending tool for applying a radial force on. said locking-key so as to depress the lockingkey radially and thus reduce its diameter to permit disassembly of the parts, said locking-key having nearly abutting ends which are provided with means for accommodating a tool extending beyond the end of the outer telescoped part for applying a circumferential force on said locking-key, so as to pull said nearly abutting ends toward each other and thus also reduce the diameter of the locking-key to permit disassembly of the parts, the groove of the inner telescoping part having sufiicient depth to permit the locking-key to be moved completely out of the groove of the outer telescoping part so as to permit said disassembly, and the inner one of said cylindrical parts being provided, at each of said plurality of points, and also in the vicinity of said nearly abutting ends, with an axially extending opening for accommodating such tools.

6. The combination including a cylindrical body-part, a ring-part which extends beyond one end of said cylindrical body-part, the inner end of said ring-part having a cylindrical bore which fits telescopically over said end of the cylindrical body-part, the engaging surfaces of the two telescoping parts having opposite annular grooves which are complementary to form a substantially closed annular chamber, and an open ring-shaped locking-key fitting within and between said opposite grooves to retain said parts together, said locking-key being resiliently biased toward an expanded position, said locking-key being provided, at each of a plurality of points spaced therealong, with means for applying a radial force on said locking-key means, so as to depress the locking-key radially and thus reduce its diameter to permit disassembly of the parts, said locking-key having nearly abutting ends which are provided with means for applying a circumferential force on said locking-key, so as to pull said nearly abutting ends toward each other and thus also reduce the diameter of the locking-key to permit disassembly of the parts, the groove of the inner telescoping part having sufficient depth to permit the locking-key to be moved completely out of the groove of the outer telescoping part so as to permit said disassembly, and the inner one of said cylindrical parts being provided, at each of said plurality of points, and also in the vicinity of said nearly abutting ends, with an axially extending opening for accommodating such force-applying means.

7. A rotor-member for a high-speed dynamo-electric machine, comprising a slotted cylindrical rotor-core having axially extending winding-receiving core-slots; a rotor- 'the respective ends of the rotor-core; slot-closing wedges for retaining said coil-side portions; a retaining ring for 'the end turns at at least one end of the rotor-Winding,

the inner end of said retaining ring fitting telescopically over its end of the rotor-core, the engaging surfaces of said telescoping ring and core having opposite annular grooves which are complementary to form a substantially closed annular chamber; and an open ring-shaped locking-key fitting within and between said opposite grooves to retain said retaining ring on its end of the rotor-core; said locking-key being provided, at spaced points corresponding to the positions'of a plurality of said slot-closing wedges, with a conformation suitable for accommodating an axially extending tool for applying a radial force on said locking-key means, so as to depress the locking-key radially and thus 'reduceits diameter to permit disassembly ofthe parts, the groove of the inner telescoping part having sufficient depth topermit the locking-key to be moved completely out of'the groove of the outer telescoping part so as to permit said 'disassem-bly.

8. A rotor-member for a high-speed dynamo-electric machine, cornprising a slotted cylindrical rotor-core having slotted winding-carrying portions, alternating with pole portions, the'winding-carrying portions having axially extending Winding-receiving core-slots; a rotor-winding having coil-side portions lying in said winding-receiving core-slots, and end turn portions ly-ing beyond the respective ends of'the rotor-core;slot-closingwedges for retaining said coil-side portions; a retaining ring for the end turns at at least one-end of the rotor-winding, the inner end of said retaining ring fitting telescopically over its end of therotor-core, the engaging surfaces of said telescoping ring and core having opposite annular grooves which are complementary to form a substantially closed annular chamber; and an-open ring-shaped locking-key 'fitting'within and-between said opposite grooves to retain said retaining ring on its end of the rotor-core; said locking-keybeing resiliently biased toward an expanded position, and having nearly abutting ends which are provided with means whereby said nearly abutting ends may be drawn together so as to reduce the diameter of the locking-key to permit disassembly of the parts; the telescoped end of the rotor-core having one or more peripheral radially and axially extending access-slots in a pole portion of said core, said access-slot or slots extendingin, axially, beyond the adjacent retaining ring, for providing access for a tool for drawing together the nearly abutting ends of the locking-key at that end of the rotor-core; said locking-key being further provided, at spaced points corresponding to-the positions of a plurality of .said slot-closing wedges, with a conformation suitable for accommodating an axially extending tool for applying a radial-force on said locking-key means, so as to depress the locking-key radially and thus reduce its diameter to permit disassembly of the parts.

References Cited in the file of this patent OTHER REFERENCES Truarc Catalogue, pages 3-5, 1947. 

